1. Field of the Invention
The present invention relates to an air bag apparatus and, more particularly, to an air bag apparatus being capable of selecting operations of air bag drivers respectively arranged for developing a plurality of air bags installed on a vehicle.
2. Description of the Related Art
Conventionally, there is proposed an air bag apparatus which detects information of the posture of a driver on a driver's seat, the presence/absence of an occupant on a passenger seat, and the posture of the occupant in a vehicle to control the operation of the air bag apparatus on the basis of the information.
More specifically, as in the main part shown in FIG. 1, an occupant sensing device 2 is connected to an air bag control device 1 through a communication line L1, and a driver's seat air bag driver 3a connected to a driver's seat air bag and a passenger seat air bag driver 3b connected to a passenger seat air bag are respectively connected to the air bag control device 1.
With this arrangement, information of the posture of the driver on the driver's seat, the presence/absence of the occupant on the passenger seat, and the posture of the occupant detected by the occupant sensing device 2 is transmitted to the air bag control device 1 through the communication line L1 to be received by the air bag control device 1.
The air bag control device 1 controls, on the basis of the received information, the driver's seat air bag driver 3a connected to the driver's seat air bag and the passenger seat air bag driver 3b connected to the passenger seat air bag.
Conventionally, there is also proposed an air bag apparatus which controls, on the basis of the will of a user of a vehicle, the operation of an air bag apparatus, e.g., the operation of the air bag apparatus such that the driver's seat air bag is developed or not and the passenger seat air bag is developed or not.
More specifically, as in the main portion shown in FIG. 2, an air bag operation selecting device 5 is connected to an air bag control device 4 through communication lines L2 and L3, and a driver's seat air bag driver 6a connected to a driver's seat air bag and a passenger seat air bag driver 6b connected to a passenger seat air bag are connected to the air bag control device 4.
With this arrangement, when the ignition switch of the vehicle is turned on, the air bag control device 4 communicates with the air bag operation selecting device 5 through the communication line L2 to determine whether the air bag operation An selecting device 5 is connected to the air bag control device 4 or not.
Next, information which indicates that the air bag operation selecting device 5 is connected to the air bag control device 4 is transmitted to the air bag control device 4 through the communication line L2.
Then, the air bag control device 4 which receives the information further receives drive selecting information, which is transmitted from the air bag operation selecting device 5 through the communication line L3, indicating whether the driver's seat air bag driver 6a is driven or not and the passenger seat air bag driver 6b is driven, etc.
As the result, the air bag control device 4 controls, on the basis of the drive selecting information received as described above, the driver's seat air bag driver 6a connected to the driver's seat air bag and the passenger seat air bag driver 6b connected to the passenger seat air bag.
Here, the air bag operation selecting device 5 is generally attached to the air bag apparatus of a vehicle in a dealer or the like after the vehicle is out from a mass production line in a vehicle assembly firm. That is, the air bag operation selecting device 5 is attached as a so-called additional device in its after market.
As described above, in the air bag apparatus for the vehicle, information is exchanged between the air bag apparatus and its peripheral device by using various communication lines.
However, as the number of communication lines increases, the number of harnesses themselves constituting the communication lines and the number of connection terminals or the like of connectors increase to cause an increase in weight and cost or to make the layout in the vehicle complex.
Therefore, the air bag apparatus installed on the vehicle in which information is highly frequently exchanged between the air bag apparatus and the peripheral device has been urged to simplify the communication system, especially, reduce communication lines in number at present.
Above all, since the additional peripheral device such as the air bag operation selecting device emerges, a need to simplify the communication system is remarkably increasing.